One of the suspects in the attack against French satirical magazine Charlie Hebdo studied in Yemen where he attended al-Qaeda training camps, Yemeni security sources and a classmate say.
Said Kouachi appeared at various times between 2009 and 2013 in the troubled Arabian peninsula country, firstly as a student at a Sanaa university known as a hotbed of Islamic fundamentalism and then at al-Qaeda training camps in the south and southeast, the sources said on Friday.
The two suspects in the Charlie Hebdo attack, Said Kouachi and his brother Cherif, were killed on Friday when police stormed the building where they were holed up, sources close to the investigation said.
Before the police raid, a French television station spoke to younger brother Cherif, who said a trip he made to Yemen in 2011 was financed by US-Yemeni radical Anwar al-Awlaki, who was killed in Yemen by an American drone strike that September.
Kouachi said they were on a mission from the Yemeni branch of the terror network, Al-Qaeda in the Arabian Peninsula (AQAP).
Shortly after Wednesday's attack at Charlie Hebdo killed 12 people, the brothers hijacked a car, telling the driver: "Say we are from Al-Qaeda in Yemen."
In 2009, Said Kouachi attended Al-Iman University, headed by fundamentalist preacher Abdel Majid al-Zindani, whose name figures on a US terror blacklist, a former Yemeni classmate said.
According to US officials, Said Kouachi was known by French intelligence to have travelled to Yemen in 2011, where he received training from AQAP in small arms combat and marksmanship.
Yemen, a key ally in US efforts to combat Al-Qaeda, has been wracked by political turmoil and violence since an uprising toppled strongman Ali Abdullah Saleh in 2012.
AQAP, formed in January 2009 as a merger of the Yemeni and Saudi branches of Al-Qaeda, is seen by Washington as the network's most dangerous branch.
The US has launched scores of drone strikes on AQAP targets in Yemen, which experts say the group has been using as a military and ideological training ground for jihadists from around the world.
Laurent Bonnefoy, a professor at Sciences Po university in Paris and an expert on Yemen, said many foreigners travel to the country to attend Koranic and Arabic language classes.
Some of the students, "who at the outset do not have a violent outlook, veer towards violence," Bonnefoy said.
Saeed al-Jamhi, a Yemeni researcher and specialist on extremist groups, said AQAP has fine-tuned "a policy of recruiting foreign elements" among students who converge on the impoverished and unstable country.
"After having trained them, AQAP leaves them free to select the targets and means to carry out" attacks, he said.
Bonnefoy agreed that "any eventual claim of responsibility does not mean that AQAP was directly involved or provided operational support".
However, Charlie Hebdo has for years been on an AQAP list of targets and Al-Qaeda's late chief Osama bin Laden warned Europe in 2008 of consequences for Prophet Mohammed cartoons published in a Danish newspaper and reproduced in the French weekly.